The majority of small form factor elongated lighting fixtures have their drivers in a remote location due to the fact that there is no room for integral drivers in those types of fixtures. These systems have performance losses caused by their long wires and are more difficult to install than integral driver fixtures.
The remote driver box fixtures are not U.L. approved for battery packs because most of the battery packs should be factory installed not field installed.
The installer have to drill thru every joist up to the last one near the fixture and route the electrical conduit from the remote driver compartment. This is additional labor and it would considerably increase the overall cost related to this job.
International residential building code prescribes limitations for notching and bored holes in both interior and exterior walls.
The decision about the location of the remote driver compartment is left to the installer and he can run into issues when he is limited by the length of the wire due to limitations imposed by manufacturer for power loss in the wire. He has to take extra steps to add up the segments of the wire way path and figure out the total length. In some situations he has to consult other people like the architect, designer, electrical engineer, building owner, contractors, etc. and incur delays due to these complexities.
For existent construction or remodeling there is a risk to interfere with electrical conduit runs, HVAC ducts or plumbing pipes as these are hidden inside the wall and most initial plans are not available or consulted before the work is started.
Those fixtures with integral driver compartment are designed as to allow driver access and maintenance, from the room side, but they require cutting and reframing structural members that are intended to support the walls and/or ceiling. This could extend or invalidate the building approvals required by the code or other authority therefore extending the overall lead time unnecessary.
Traditional shallow elongated recessed fixtures are not usually designed to allow access to replace the light engine while the maintenance of their remote drivers is more difficult than of those fixtures with integral driver.
The warranty for the L.E.D. driver is usually under 5 years while LEDs could have double that lifetime.
The power input of these runs is usually at the end of the fixture. Most of the walls and ceilings would have structural joist members at corner or at the end edges therefore these fixtures are not versatile and are not designed for what is mostly needed: end to end, transition corners, etc.
Most of the other fixtures could not be installed after the planar surface is up, on existent construction. Most of them are for new construction and to be installed before the planar surface is installed.
Various fixtures have been proposed to secure the light sources to the architectural surfaces. Typically, these fixtures have a relatively large depth profile that necessitates excessive clearance space behind the ceiling, wall, or floor surface. In most cases, it may be necessary to reframe a wall to add sufficient depth for the lighting fixture, which may also require cutting and reframing window sills, headers, and other architectural features for structural continuity.
Due to its housing depth and because it's installed to the structure with screws, the integral fixture opening is distorted making the opening variable along the length of the fixture which in turn is not accurate enough to install the light diffusing/converting optical elements like: extruded lens, covers, etc. Additional temporary brackets are used to brace and bridge this opening but they don't eliminate completely the effect and/or they don't control the cause of the distortion (deep housing profile, unknown screw torque force applied by the installed in the field).